The invention relates to a door closing arrangement for controlling the closure sequence of turnable double doors.
In order to lock together the door leaves of a double door one of the door leaves, a so-called primary door leaf, is preferably provided with a latch bolt. As a consequence, it is necessary for the door leaves to be closed in a certain order so that the primary door leaf provided with the latch bolt is closed after the other door leaf (the secondary door leaf). Thus the spring-loaded latch bolt may, due to its bevelled guide surface, be forced into the lock body in the primary door in order to fully close the primary door. In this position the latch bolt may, forced by the spring, move again to its protruding position, in which it engages the secondary door leaf and locks the door leaves together. Several different approaches for controlling the closure sequence of a double door are known from the prior art.
Depending on the situation the door closers may be installed in a double door so that the door closers are located either on the same side of their respective door leaves as the hinges or on the side opposite to the hinges. In the latter case the problem is that the distal end of the pull arm of the door closer, i.e. the end that is more distant from the door closer mechanism, changes its direction of movement when the door leaf approaches its fully closed position. Consequently, it is difficult to control the closure sequence of the doors and this often makes it necessary to release the primary door even if the secondary door is still somewhat open.
U.S. patent application Publication No. 2001/0025450-A1 discloses an arrangement which is based on the idea that the releasing effect of the secondary door leaf on the closure sequence control mechanism, i.e. the mechanism that prevents premature closing of the primary door leaf, is accomplished by providing a pulling force which makes the blocking member included in the closure sequence control mechanism allow the closing of the primary door leaf. In case the door closers are installed on the same side of the door leaves as the door hinges, whereby no change occurs in the direction of movement of the distal end of the pull arm during the closing phase of the door leaves, the release of the closure sequence control mechanism takes the conventional form of a pushing movement. Such being the case, different arrangements for controlling closure sequences are required, depending on the way in which the door closers are installed.
An embodiment of the present invention provides a novel and improved arrangement to be applied to the case in which the door closers are installed to the respective door leaves on the sides opposite to the door hinges. The invention may be used to provide an arrangement that is simple in construction and has a reliable operation and by which the above-mentioned drawbacks in the prior art arrangements can be eliminated or at least reduced.